Ultrasonic transducer excitation circuit and ultrasonic transducer

Abstract

The invention discloses an ultrasonic transducer excitation circuit and an ultrasonic transducer. According to the technical scheme, the device comprises a central control module, an ultrasonic waveform generation module, a program control voltage source module and a full-bridge driving module; the central control module at least has a serial port communication function, and receives a parameter setting instruction of an upper computer through serial port communication to control the whole system; the ultrasonic waveform generation module comprises a sine wave generation module and a pulse square wave conversion module, and the sine wave generation module generates a sine wave signal with a specified frequency. The system has the advantages that the parameter adjustment flexibility is high, the ultrasonic waveform is generated by the central control module, the basic frequency, the pulse frequency and the pulse width all have the characteristics of wide range, flexibility and adjustability, personalized definition of a user is supported, and various application requirements are met.

Description

Technical Field

[0001] The invention belongs to the field of ultrasonic treatment equipment, and in particular relates to an ultrasonic transducer excitation circuit. Background Art

[0002] The main task of the ultrasonic excitation circuit is to provide appropriate electrical signals to the ultrasonic transducer, which converts these electrical signals into ultrasonic energy to produce a therapeutic effect in the target tissue. The excitation circuit provides an AC signal to the transducer, and the piezoelectric material (such as piezoelectric ceramics or piezoelectric crystals) inside the transducer deforms under the action of the electrical signal, thereby generating mechanical vibrations. This mechanical vibration is further converted into ultrasonic energy, which acts on the tissue to produce a therapeutic effect. The frequency of the ultrasonic wave depends on the frequency of the electrical signal provided by the excitation circuit, while the intensity of the ultrasonic wave is related to the amplitude of the electrical signal. By adjusting the output frequency and signal amplitude of the excitation circuit, the device can control the characteristics of the ultrasonic wave generated by the transducer. The electrical signal generated by the excitation circuit can be a continuous wave or a pulse wave, depending on the treatment needs. For example, a continuous wave is used for long-term stable energy transmission, while a pulse wave helps to intermittently stimulate the tissue while reducing the total average power. By adjusting the parameters of the excitation circuit, such as signal amplitude, fundamental frequency, pulse frequency, duty cycle, and intermittent duration, the device can accurately control the intensity and duration of the ultrasonic wave, thereby customizing the treatment plan. This has important implications for different types of tissues and conditions, especially where precise control of energy delivery is required.

[0003] The mainstream ultrasonic excitation circuit consists of an ultrasonic signal source and an ultrasonic power amplifier. At present, the mainstream ultrasonic signal source has the problems of single signal mode, few adjustable parameters or insufficient adjustable range. Traditional mainstream ultrasonic power amplifiers include RF power amplifier direct drive, self-excited oscillation drive and half-bridge / full-bridge inverter circuits. RF power amplifier direct drive requires a power supply with higher signal fidelity and a RF power amplifier with wider bandwidth and higher power. Its overall circuit structure is relatively complex and the cost is high. The self-excited oscillation circuit has poor frequency stability and poor applicability, and cannot accurately control ultrasonic time and power parameters. Half-bridge / full-bridge inverter circuits are prone to electromagnetic interference (EMI) and noise when working at high frequencies, and have high requirements for high-frequency transformers. Moreover, these traditional mainstream ultrasonic power amplifiers cannot directly and accurately control the drive amplitude. In order to solve the above problems, the present invention aims to propose a method to meet the complex ultrasonic treatment needs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an ultrasonic transducer excitation circuit and an ultrasonic transducer with simple structure and flexible control.

[0005] To solve the above problems, the technical solution adopted by the present invention includes: a central control module, an ultrasonic wave waveform generation module, a programmable voltage source module and a full-bridge drive module; The central control module at least has a serial communication function, and receives parameter setting instructions from the host computer through serial communication to control the entire system; The ultrasonic waveform generation module includes a sine wave generation module and a pulse square wave conversion module. The sine wave generation module generates a sine wave signal of a specified frequency, and then generates a pair of square wave waveforms with opposite phases in the form of pulse groups through the pulse square wave conversion module. The basic frequency of the square wave waveform is equal to that of the sine wave, and the pulse frequency and width of the pulse group are adjustable. This pair of anti-phase signals is used to control the two half bridges of the full-bridge drive module; the module-controlled voltage source block receives the control instruction of the central control module to accurately generate a voltage source with an amplitude at a specific voltage value and sufficient current output capacity; The full-bridge drive module is composed of a full-bridge drive waveform generation module and a full-bridge drive power amplifier module. The full-bridge drive power amplifier module includes two pairs of transistors Q connected up and down. 1 , transistor Q 2 , transistor Q 3 and transistor Q 4 The full-bridge drive waveform generation module includes a pair of anti-phase ultrasonic waveforms emitted in the form of pulse groups to generate and control the transistor Q 1 , transistor Q 2 , transistor Q 3 and transistor Q 4 signal.

[0006] The system also includes an impedance matching module, which is used to change the equivalent impedance of the loaded ultrasonic transducer at the excitation signal output port; by reducing or increasing the equivalent impedance of the loaded ultrasonic transducer, the output power of the ultrasonic transducer is increased to improve the output efficiency, or the output power is reduced so that the output power of the ultrasonic transducer can be fine-tuned more accurately within a smaller range.

[0007] The parameter setting instructions include setting the ultrasonic output mode, output base frequency, pulse frequency, duty cycle and intermittent duration, and controlling the ultrasonic waveform generation module, amplitude adjustment module and full-bridge drive module according to the parameter setting instructions to output the required ultrasonic excitation signal.

[0008] The ultrasonic waveform generation module generates at least four different modes of ultrasonic waveforms, including single-pulse ultrasonic wave, continuous ultrasonic wave, continuous pulse ultrasonic wave and intermittent pulse ultrasonic wave. The adjustable parameters of ultrasonic stimulation of each ultrasonic waveform mode include ultrasonic excitation signal amplitude, basic frequency, repetition pulse width, repetition pulse frequency, stimulation duration, stimulation interval duration and total stimulation duration.

[0009] The power supply of the full-bridge driving module is provided by a programmable voltage source module.

[0010] The programmable voltage source module adopts a DCDC module with adjustable output voltage. The output voltage of the DCDC module is adjusted by negative feedback. The control voltage V ctrl Through the resistor R 2 Series coupled to V fb The negative feedback function of the negative feedback network adjusts the output supply voltage V p And through the resistor R 0 and resistor R 1 The feedback node voltage V fb Stable at a specific amplitude, its expression is .

[0011] When the full-bridge drive waveform generating module receives a pair of inverted ultrasonic waveform signals generated by the ultrasonic waveform generating module, the pair of inverted signals respectively generate independent control signals for four transistors via the dead zone generator and the level converter; wherein the dead zone generator delays the edge of the control signal so that the transistor Q 1 and transistor Q 2 or transistor Q 3 and transistor Q 4 There is a dead time in the process of alternating switching of the transistor, and during this dead time, the transistor Q 1 and transistor Q 2 or transistor Q 3 and transistor Q 4 In disconnected state.

[0012] The level converter transfers the control signal from the low voltage domain to the high voltage domain so that the transistor Q 1 and transistor Q 3 The gate-source voltage will remain constant during the conduction process as the source voltage rises.

[0013] The impedance matching module includes a load impedance increasing type matching network and a load impedance decreasing type matching network. The load impedance decreasing type matching network is divided into two types: the first type is to first connect the load ultrasonic transducer in parallel with the first inductor and then connect it in series with the first capacitor and then connect it to the drive output terminal; the second type is to first connect the load ultrasonic transducer in parallel with the second capacitor and then connect it in series with the second inductor and then connect it to the drive output terminal. The load impedance increasing type matching network is divided into two types: the first type is to first connect the load ultrasonic transducer in series with the third capacitor and then connect it in parallel with the third inductor and then connect it to the drive output terminal; the second type is to first connect the load ultrasonic transducer in series with the fourth inductor and then connect it in parallel with the fourth capacitor and then connect it to the drive output terminal.

[0014] An ultrasonic transducer is provided with the ultrasonic transducer excitation circuit described in any one of the above items.

[0015] The ultrasonic transducer excitation circuit of the present invention has the following advantages: 1. High flexibility in parameter adjustment: The ultrasonic waveform is generated by the central control module. The basic frequency, pulse frequency and pulse width are all flexible and adjustable in a wide range, supporting users to make personalized definitions to meet various application requirements; 2. Large drive output bandwidth and strong output current capability: The full-bridge drive circuit structure is adopted, and the output bandwidth is significantly better than the traditional RF power amplifier circuit. The design can achieve a bandwidth of 20MHz or even higher, which can cover the frequency requirements of all ultrasonic transducers on the market. In addition, the drive current range is wide, supporting outputs of several amperes to tens of amperes within the full bandwidth and full amplitude range; 3. The adjustable range of the drive output amplitude is large and accurate: the drive output amplitude is directly controlled by the power supply voltage of the full-bridge drive circuit, and the power supply voltage is accurately provided by the programmable voltage source module. Compared with the traditional gain coefficient adjustment method, this method can achieve high-precision, wide-range linear adjustment of the output amplitude, and the control is more accurate; 4. Ultrasonic waveform has strong anti-interference ability: The ultrasonic waveform adopts square wave form, which has excellent anti-interference performance and high fault tolerance, reduces the requirements for the signal-to-noise ratio of the analog circuit module, and improves the reliability of the system; 5. Simple circuit structure and low cost: The overall circuit adopts modular design. The functions of each module are clear and easy to replace and maintain separately. The circuit structure of each module is simple, and the design complexity and manufacturing cost are low.

[0016] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a circuit schematic diagram of an ultrasonic transducer excitation circuit system of the present invention; Figure 2 Schematic diagram of the waveform of a single pulse ultrasonic wave of the present invention; Figure 3 It is a waveform diagram of continuous ultrasonic wave of the present invention; Figure 4 It is a waveform diagram of the continuous pulsed ultrasonic wave of the present invention; Figure 5 1 is a waveform diagram of the intermittent pulsed ultrasonic wave of the present invention; Figure 6 Schematic diagram of input and output waveforms of the pulse-to-square wave conversion module of the present invention; Figure 7 It is a circuit schematic diagram of the full-bridge drive power amplifier module of the present invention; Figure 8It is a circuit schematic diagram of the dead zone generator and the level converter of the present invention; Fig. 9 is a timing diagram of various control signals of the present invention and the potential difference applied to the load ultrasonic transducer; Fig.10 Is a circuit diagram of the impedance matching module of the present invention; Fig.11 It is a feedback network diagram of the DCDC module of the present invention. DETAILED DESCRIPTION

[0018] Embodiment 1:

[0019] Reference Figure 1-Figure 11 As shown, the ultrasonic transducer excitation circuit of the present invention is composed of a central control module 1, an ultrasonic wave shape generating module 2, a programmable voltage source module 3, a full-bridge driving module 4 and an optional impedance matching module 5.

[0020] Among them, the central control module 1 adopts a microprocessor commonly used in embedded systems such as a single-chip microcomputer chip or an FPGA chip, and needs to have a serial communication function to receive parameter setting instructions from a host computer through serial communication to control the entire system. The host computer can be a computer, a touch screen or any user interaction module that can perform serial communication.

[0021] The ultrasonic waveform generation module 2 is used to generate the required ultrasonic waveform signal, which includes a sine wave generation module 21 and a pulse square wave conversion module 22; the sine wave generation module 21 has the function of outputting a single frequency sine wave signal, and the frequency of the sine wave signal is the frequency of the required ultrasonic signal. The sine wave signal is converted into a pair of inverse square wave signals in the form of pulse groups through the pulse square wave conversion module. The pulse frequency and width of the pulse group are adjustable. The input and output waveforms are as follows: Figure 6 The ultrasonic waveform generation module 2 can generate four different ultrasonic waves by intermittently outputting and adjusting the pulse width and frequency, including: Figure 2 Continuous ultrasound, such as Figure 3 The single pulse ultrasound shown in Figure 4 The continuous pulsed ultrasound shown and Figure 5The intermittent pulsed ultrasound shown in the figure can meet the needs of different treatment scenarios. The parameters that need to be adjusted in different modes of ultrasonic stimulation include the ultrasonic excitation signal amplitude Amp (Amplitude), ultrasonic fundamental frequency FF (Fundamental Frequency), ultrasonic repetition pulse width PD (Pulse Duration), ultrasonic repetition pulse frequency PRF (Pulse Repetition Frequency), ultrasonic stimulation duration SD (Sonication Duration), ultrasonic stimulation intermittent duration ISI (Inter-stimulation Interval) and total ultrasonic stimulation duration TSD (Total Sonication Duration). The continuous ultrasonic stimulation is to continuously and uninterruptedly output the ultrasonic excitation signal within the specified TSD; the single-pulse ultrasonic stimulation refers to the output of an ultrasonic excitation signal with a PD duration. The difference is that the TSD of the continuous ultrasonic stimulation is generally in the second or minute level, while the PD of the single-pulse ultrasonic stimulation is generally in the microsecond or millisecond level. The continuous pulse ultrasonic stimulation refers to the continuous output of ultrasonic excitation signals in the form of pulse groups within a specified TSD; the intermittent pulse ultrasonic stimulation refers to the intermittent output of ultrasonic excitation signals in the form of pulse groups with a duration of SD at intervals of ISI within a specified TSD.

[0022] The programmable voltage source module 3 generates a power supply voltage V with a required ultrasonic excitation signal amplitude Amp level and sufficient current output capacity after receiving the control instruction of the central control module 1. p Preferably, the programmable voltage source module 3 in this specific embodiment adopts a DCDC module with adjustable output voltage. The output voltage of the DCDC module is adjusted by negative feedback, and the control voltage V ctrl Through the resistor R 2 Series coupled to V fb The negative feedback function of the negative feedback network adjusts the output supply voltage V p And through the resistor R 0 and resistor R 1 The feedback node voltage V fb Stable at a specific amplitude, its expression is .

[0023] The full-bridge driving module 4 amplifies the ultrasonic waveform signal generated by the ultrasonic waveform generating module 2 to the supply voltage Vp of the ultrasonic excitation signal amplitude Amp level generated by the programmable voltage source 3 and makes the current output capacity sufficient to drive the load ultrasonic transducer 6. The full-bridge driving module 4 is composed of a full-bridge driving waveform generating module 41 and a full-bridge driving power amplifying module 42. The full-bridge driving power amplifying module 42 is composed of two pairs of transistors Q connected up and down. 1 , transistor Q 2 , transistor Q 3 and transistor Q 4 The transistor Q 1 , transistor Q 2 , transistor Q 3 and transistor Q 4 NMOS transistors are ideal. Their structure is as follows Figure 7 As shown, each of the transistors is controlled by a separate signal. Further: the control signals of the four transistors are generated by the full-bridge drive waveform generation module 41. The full-bridge drive waveform generation module 41 receives a pair of inverted ultrasonic waveform signals generated by the ultrasonic waveform generation module 2, and the pair of inverted signals respectively generate control signals for the four transistors via the dead zone generator 411 and the level converter 412. The dead zone generator 411 delays the edge of the control signal so that the transistor Q 1 and transistor Q 2 or transistor Q 3 and transistor Q 4 There is a dead time during the alternating switching process. During this dead time, the transistor Q 1 and transistor Q 2 or transistor Q 3 and transistor Q 4 At the same time, it is in the disconnected state, avoiding the risk of short circuit from the supply voltage Vp output from the DCDC module 32 to the ground. Further: the level converter 412 transfers the control signal from the low voltage domain to the high voltage domain, so that the transistor Q 1 and Q 3 The gate-source voltage of the transistor will remain unchanged during the conduction process as the source voltage rises, ensuring that the transistor Q 1 and transistor Q 3 The timing of each control signal and the potential difference applied to the load ultrasonic transducer is as follows: Fig. 9 Further: the power supply of the full-bridge driving module is provided by the amplitude adjustment module, so as to accurately and flexibly adjust the voltage amplitude of the excitation signal output by the driving.

[0024] Wherein, the impedance matching module 5 is an optional module, which can be flexibly designed according to the load circuit driven as needed. The impedance matching module 5 is used to change the equivalent impedance of the loaded ultrasonic transducer at the output port of the excitation signal. By reducing or increasing the equivalent impedance of the loaded ultrasonic transducer, the output power of the ultrasonic transducer is increased to improve the output efficiency, or the output power is reduced so that the output power of the ultrasonic transducer can be more accurately fine-tuned within a smaller range. The impedance matching module 5 includes a matching network for increasing load impedance and a matching network for reducing load impedance. Wherein, the matching network for reducing load impedance is divided into two types: the first matching network for reducing load impedance 51 or the second matching network for reducing load impedance 52 can be selected to increase the output power so that the output power can reach a larger range. The first matching network for reducing load impedance 51 first connects the loaded ultrasonic transducer 6 in parallel with the first inductor 512 and then in series with the first capacitor 511 and then connected to the drive output end. The second matching network for reducing load impedance 52 first connects the loaded ultrasonic transducer 6 in parallel with the second capacitor 522 and then in series with the second inductor 521 and then connected to the drive output end. The load impedance-enhanced matching network is also divided into two types: the first load impedance-enhanced matching network 53 or the second load impedance-enhanced matching network 54 is selected to reduce the output power, so that the output power can be adjusted more finely within a lower range. The first load impedance-enhanced matching network 53 first connects the loaded ultrasonic transducer in series with the third capacitor 531 and then in parallel with the third inductor 532, and then connects it to the drive output end. The second load impedance-enhanced matching network 54 first connects the loaded ultrasonic transducer in series with the fourth inductor 541 and then in parallel with the fourth capacitor 542, and then connects it to the drive output end. The impedance matching module 5 can also be omitted, and the drive output end is directly connected to the loaded ultrasonic transducer, which can also achieve the purpose of driving the ultrasonic transducer, but does not have the adjustment function. Embodiment 2:

[0025] Reference Figure 1-Figure 11 As shown, an ultrasonic transducer of the present invention is provided with the ultrasonic transducer excitation circuit described in Example 1. The ultrasonic transducer is mainly used in ultrasonic diagnostic devices.

[0026] The above does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of the structure and technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An ultrasonic transducer excitation circuit, characterized in that ,The system includes: a central control module, an ultrasonic wave profile generation module, a programmable voltage source module and a full-bridge drive module; The central control module receives parameter setting instructions from the host computer through serial communication to control the entire system; The ultrasonic waveform generation module includes a sine wave generation module and a pulse square wave conversion module. The sine wave generation module generates a sine wave signal of a specified frequency, and then generates a pair of square wave waveforms with opposite phases transmitted in the form of pulse groups through the pulse square wave conversion module. The basic frequency of the square wave waveform is equal to that of the sine wave, and the pulse frequency and width of the pulse group are adjustable. This pair of anti-phase signals is used to control the two half bridges of the full-bridge driving module; The program-controlled voltage source block receives the control instruction of the central control module to accurately generate a voltage source with a specific voltage amplitude and current output capability; The full-bridge drive module is composed of a full-bridge drive waveform generation module and a full-bridge drive power amplifier module. The full-bridge drive power amplifier module includes two pairs of transistors Q1, transistor Q2, transistor Q3 and transistor Q4 connected up and down. The full-bridge drive waveform generation module generates signals that individually control the transistors Q1, transistor Q2, transistor Q3 and transistor Q4, thereby outputting ultrasonic excitation signals emitted in the form of pulse groups.

2. The ultrasonic transducer excitation circuit according to claim 1, characterized in that: The system also includes an impedance matching module, which is used to change the equivalent impedance of the loaded ultrasonic transducer at the excitation signal output port; by reducing or increasing the equivalent impedance of the loaded ultrasonic transducer, the output power of the ultrasonic transducer is increased to improve the output efficiency, or the output power is reduced so that the output power of the ultrasonic transducer can be fine-tuned more accurately within a smaller range.

3. The ultrasonic transducer excitation circuit according to claim 1, characterized in that: The parameter setting instructions include setting the ultrasonic output mode, output base frequency, pulse frequency, duty cycle and intermittent duration, and controlling the ultrasonic waveform generation module, amplitude adjustment module and full-bridge drive module according to the parameter setting instructions to output the required ultrasonic excitation signal.

4. The ultrasonic transducer excitation circuit according to claim 1, characterized in that: The ultrasonic waveform generation module generates at least four different modes of ultrasonic waveforms, including single-pulse ultrasonic wave, continuous ultrasonic wave, continuous pulse ultrasonic wave and intermittent pulse ultrasonic wave. The adjustable parameters of ultrasonic stimulation of each ultrasonic waveform mode include ultrasonic excitation signal amplitude, basic frequency, repetition pulse width, repetition pulse frequency, stimulation duration, stimulation interval duration and total stimulation duration.

5. The ultrasonic transducer excitation circuit according to claim 1, characterized in that: The power supply of the full-bridge driving module is provided by a programmable voltage source module.

6. The ultrasonic transducer excitation circuit according to claim 5, characterized in that: The programmable voltage source module adopts a DCDC module with adjustable output voltage. The output voltage of the DCDC module is adjusted by negative feedback. The control voltage V ctrl Coupled in series to V through resistor R2 fb The negative feedback function of the negative feedback network adjusts the output supply voltage V p The feedback node voltage V fb Stable at a specific amplitude, its expression is .

7. The ultrasonic transducer excitation circuit according to claim 1, characterized in that: When the full-bridge drive waveform generating module receives a pair of inverted ultrasonic waveform signals generated by the ultrasonic waveform generating module, the pair of inverted signals generates independent control signals for four transistors via a dead zone generator and a level converter respectively; wherein the dead zone generator delays the edge of the control signal so that there is a dead zone time during the alternating switching of the transistors Q1 and Q2 or the transistors Q3 and Q4, and during the dead zone time, the transistors Q1 and Q2 or the transistors Q3 and Q4 are simultaneously in an off state.

8. The ultrasonic transducer excitation circuit according to claim 7, characterized in that: The level converter transfers the control signal from the low voltage domain to the high voltage domain, so that the gate-source voltage of the transistor Q1 and the transistor Q3 can remain unchanged during the conduction process as the source voltage increases.

9. The ultrasonic transducer excitation circuit according to claim 2, characterized in that: The impedance matching module includes a matching network for increasing load impedance and a matching network for reducing load impedance. The load impedance reduction type matching network is divided into two types: the first type is to first connect the loaded ultrasonic transducer in parallel with the first inductor and then connect them in series with the first capacitor before connecting to the drive output end; the second type is to first connect the loaded ultrasonic transducer in parallel with the second capacitor and then connect them in series with the second inductor before connecting to the drive output end; the load impedance increase type matching network is divided into two types: the first type is to first connect the loaded ultrasonic transducer in series with the third capacitor and then connect them in parallel with the third inductor before connecting to the drive output end; the second type is to first connect the loaded ultrasonic transducer in series with the fourth inductor and then connect them in parallel with the fourth capacitor before connecting to the drive output end.

10. An ultrasonic transducer, characterized in that: The ultrasonic transducer is provided with the ultrasonic transducer excitation circuit described in any one of claims 1-9.

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